Plasmacytomas can be induced in the inbred BALB/c mouse by mineral oils and pure alkanes. The effect of the oil is to create an abnormal tissue microenvironment in which the tumors develop. We are studying the oil granuloma environment for its ability to stimulate the growth of plasmacytomas and its suppressive effects on host immunity to plasmacytomas. The role of viral and chemical initiators, and specific genes in plasmacytoma formation, are being examined. The antigen-binding myeloma proteins of mice are forms of homogeneous antibodies that can be used to analyze antibody structure. We isolate groups of myeloma proteins that bind the same hapten, determine their amino acid sequences, and crystal structure. The intraperitoneal injection of mineral oil (priming) creates an abnormal tissue environment long before the tumors appear. This has been demonstrated by successful growth of small numbers of plasmacytoma cells from a primary host, in the mineral oil conditioned peritoneum. Priming locally stimulates growth of, and abrogates established immunity to, an antigeneic transplantable plasmacytoma. Abelson virus, infection in 5 to 8 weeks after mineral oil injection, results in the rapid development of plasmacytomas and lymphosarcomas. The genetic basis of susceptibility of the BALB/c mouse is being investigated. Abelson virus induces lymphocytic B-cell neoplasms with surface immunoglobulin. We are investigating the biology and functional properties of these tumors. Genetics and structure of antigen binding myeloma proteins continues with an effort to find new markers and map the IgCH locus.